Sure.
You can create a "Group Promotions", where your users can join to X group if they meet the requeriments that you want. For that, just go to: Users & Groups -> Groups Promotion -> Add new promotion
I hope you can get it. Just tell me if you don't understand me.

But, that you're telling me, is the "Group Promotions" setting.
When you do that, they can join from UserCP. Then you can choose who will be the group leader.
Just try it, and you'll see that it's the same.
EDIT:
(I realize that i'm telling you it's not exactly that you want, but it's something like you want)
But I still think that It's not necesary a plugin to do that you want.